Year	% of expense
1991	2.1569951725324743
1992	1.5758197954065774
1993	1.510472680938633
1994	1.720008098561764
1995	6.079651090087066
1996	5.189880353927862
1997	5.181214067964738
1998	5.312685220302328
1999	4.998252403161477
2000	5.2504266291241075
2001	5.615016176332677
2002	4.886778123974585
2003	4.729569630319523
2004	5.25674339185261
2005	5.484155920918584
2006	5.398332919781628
2007	4.84397815013706
2008	5.14733760597679
2009	5.427575756820658
2010	5.323195858283406
2011	5.274339892776091
2012	5.5463463873766985
2013	5.3522315903163165
2014	5.034015609542426
2015	5.020406245132856
2016	4.974916247953536
2017	5.2929302337667234
2018	5.186196642210364
2019	5.086611424211759
2020	5.058362118549145
2021	5.388919836169582
2022	6.211250166467729